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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

36790 results found.

  1. Fermi trigger No 746438824: Global MASTER-Net observations report
  2. SVOM GRB 240821A: optical afterglow discovery
  3. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  4. GRB 240828A: Fermi GBM Final Real-time Localization
  5. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  6. GRB 240825A: GECAM detection
  7. GRB 240825A: ALMA detection
  8. GRB 240825A: SAO RAS optical observations
  9. GRB 240824A: GIT optical upper limit
  10. GRB 240819A: Swift afterglow confirmation
  11. GRB 240825A: TNG optical photometry and spectroscopy
  12. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  13. GRB 240825A: GMG Continued Optical Observation on the Second Night
  14. GRB 240824B: Ondrejov D50 optical limit
  15. GRB 240825A: KAIT optical observations
  16. GRB 240825A: PRIME near-infrared detection
  17. Konus-Wind detection of GRB 240825A (bright/long)
  18. GRB 240825A: Fermi GBM Observation
  19. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  20. GRB 240825A: AKO Optical Follow-Up Observations
  21. GRB 240825A: AstroSat CZTI detection of the long bright burst
  22. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  23. GRB 240825A: Swift/UVOT Detection
  24. GRB 240825A: REM detection of the optical/NIR afterglow
  25. GRB 240825A: Swift-XRT refined Analysis
  26. GRB 240825A: VLT/X-shooter redshift
  27. GRB 240825A: SVOM/C-GFT optical observations
  28. GRB 240825A: Montarrenti Observatory optical observations
  29. GRB 240825A: Enhanced Swift-XRT position
  30. GRB 240825A: MASTER optical counterpart observation
  31. GRB 240825A: Fermi-LAT detection
  32. GRB 240825A: LCO optical observations
  33. GRB 240824B: KAIT optical upper limit
  34. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  35. GRB 240824B: Fermi GBM Observation
  36. Fermi GRB 240825A: Global MASTER-Net observations report
  37. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  38. GRB 240824B: NOT optical upper limit
  39. GRB 240825A: GMG Optical Observation
  40. Swift GRB 240825A: Global MASTER-Net observations report
  41. GRB 240825A: 1.6m Mephisto multi-band detection
  42. GRB 240825A: AKO Optical Afterglow Detection
  43. GRB 240825A: Skynet Optical Afterglow observations
  44. GRB 240825A: Nanshan/HMT optical afterglow observations
  45. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  46. GRB 240825A: Fermi GBM Final Real-time Localization
  47. GRB 240824A: Swift-BAT refined analysis
  48. GRB 240824A: SVOM/C-GFT optical upper limit
  49. GRB 240824B: Swift-XRT afterglow detection
  50. GRB 240824A: Swift-XRT observations
  51. GRB 240824B: Swift/BAT arcminute localization of a burst
  52. GRB 240824B: Swift ToO observations
  53. Fermi GRB 240824C: Global MASTER-Net observations report
  54. GRB 240824C: Fermi GBM Final Localization
  55. GRB 240824A: Swift/UVOT Upper Limits
  56. GRB 240821A: Swift/UVOT observations of the XRT sources.
  57. GRB 240824B: MAXI/GSC detection
  58. GRB 240824B: Fermi GBM Final Real-time Localization
  59. GRB 240824A: Retraction of GCN 37255
  60. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  61. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  62. GRB 240824A: KAIT optical upper limit
  63. GRB 240824A: Skynet Optical Afterglow Discovery
  64. GRB 240824A: Swift detection of a burst
  65. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  66. GRB 240821A: Colibri Optical Upper Limit
  67. GRB 240821A: Swift-XRT observations
  68. GRB 240822A: AstroSat CZTI detection of a short burst
  69. GRB 240821A: REM optical/NIR upper limits
  70. GRB 240821A: LCO optical observations
  71. GRB 240821A: JinShan optical upper limits
  72. GRB 240809A: Mondy and AbAO Optical Observations
  73. GRB 240821A: SVOM/VT follow-up and optical upper limit
  74. GRB 240821A: GMG Optical Upper Limit
  75. Fermi GRB 240821A: Global MASTER-Net observations report
  76. GRB 240821A: Fermi GBM Observation
  77. Fermi trigger No 745964969: Global MASTER-Net observations report
  78. Fermi trigger No 745925274: Global MASTER-Net observations report
  79. GRB 240821A: Swift ToO observations
  80. Fermi trigger No 746019401: Global MASTER-Net observations report
  81. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  82. Fermi trigger No 745935375: Global MASTER-Net observations report
  83. GRB240821A: EIRSAT-1 GMOD Detection
  84. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  85. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  86. Fermi GRB 240821B: Global MASTER-Net observations report
  87. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  88. GRB 240821A: SVOM/GRM observation
  89. GRB 240821A: SVOM/GRM observation
  90. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  91. GRB 240821B: Fermi GBM Final Localization
  92. Fermi trigger No 745866488: Global MASTER-Net observations report
  93. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  94. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  95. GRB 240821A: Fermi GBM Final Real-time Localization
  96. GRB 240819A: Swift-XRT observations
  97. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  98. GRB 240820B: SVOM/GRM observation
  99. GRB 240819A: KAIT optical upper limit
  100. Fermi trigger No 745873283: Global MASTER-Net observations report

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